Mechanical apparatus for electrodeposition of cans

ABSTRACT

An automatic electrodeposition machine which electrodeposits a coating onto a metal can body. A number of batches of cans are moved in a series to a position above a coating solution bath and are lowered into the coating solution bath where coating is electrodeposited onto the cans. After electrodeposition has taken place, the coated cans are removed from the coating solution and are passed through an airblast which removes such of the coating solution as has adhered to the sides of the cans. The car bodies are then passed through a water rinse, then an airblast. The water rinse is made with deionized water because ordinary water leaves spots of material on the cans. Can bodies are now passed through any series of water rinses, airblasts, and the like, which may be deemed desirable in the circumstances, and finally, go into an oven. At the conclusion of these processes, a clean, coated can is obtained.

United States Patent 3,083,7l6 4/1963 Rowanetal..... 3,276,983

inventor Wayne T. Chinppe Western Springs, Ill.

App]. No. 829,411

Filed June 2, 1969 Patented Nov. 16, 1971 Assignee Continental Can Company, Inc.

New York, N.Y.

MECHANICAL APPARATUS FOR ELECTRODEPOSITION OF CANS 10 Claims, 6 Drawing Figs.

U.S. Cl 204/198, 204/26 Int. Cl 365g 49/04 Field of Search 198/33 R, 77; 134/67,?3, l33;204/26, I98, 300

References Cited UNITED STATES PATENTS 10/1966 Dolan etal.

Primary Examiner-John H. Mack Assistant Examiner-William 1. Solomon AttorneysAmericus Mitchell, Joseph E. Kerwin and William A. Dittmann ABSTRACT: An automatic electrodeposition machine which electrodeposits a coating onto a metal can body. A number of batches of cans are moved in a series to a position above a coating solution bath and are lowered into the coating solution bath where coating is electrodeposited onto the cans. After electrodeposition has taken place, the coated cans are removed from the coating solution and are passed through an airblast which removes such of the coating solution as has adhered to the sides of the cans. The car bodies are then passed through a water rinse, then an airblast. The water rinse is made with deionized water because ordinary water leaves spots of material on the cans. Can bodies are now passed through any series of water rinses, airblasts, and the like, which may be deemed desirable in the circumstances, and finally, go into an oven. At the conclusion of these processes, a clean, coated can is obtained.

PAIENTEmmv 1s usn SHEET 1 BF INVENTOR WAYNE T CH/APPE BY W PATENTEnuuv '1 6 I97! 3,6 20. 9 5 2 sum 2 or 3 INVENTOR WAYNE T CHIA PPE ATT'Y MECHANICAL APPARATUS FOR ELEC'I'RODEPOSI'I'ION F CANS My invention is drawn to an automatic batch electrodeposition apparatus for cans, and specifically, a batch electrodepositing apparatus for depositing a coating on the can bodies.

It is an object of my invention to provide a machine for automatically coating can bodies in batches.

It is another object of my invention to provide a can body feed system for isolating batches of can bodies and feeding them into, through, and out of the coating machine.

It is a final object of my invention to provide even and regular coating of the can bodies.

In brief, my invention is drawn to the isolating of a batch of can bodies, and dipping a batch of can bodies into an electroplating solution where they are plated. The batch of can bodies is now airblasted to dryness, washed with deionized water, and air blasted to dryness again. After repetition of the rinsing and drying, the can body is ready for further manufacturing operations.

The above and other objects will become apparent from the following description and drawings in which:

FIG. 1 shows a front view apparatus of my invention;

FIG. 2 shows a partial top view of my apparatus;

FIG. 3 shows a cross section of FIG. 1 taken along line 3-3 showing the discharge bar in its lower position;

FIG. 4 shows a top view of a section of the mounting plate;

FIG. 5 shows a cross section taken along the line 5-5 of FIG. 4; and

FIG. 6 shows a schematic diagram of the control system.

My machine is adapted to be positioned in a can-processing line after the can bodies have been formed. These bodies have neither top nor bottom. As shown in FIG. 1, the can body 1, after being formed, is placed upon a conveyor belt 2. The conveyor belt may be of any suitable material, such as woven mesh wire or mesh chain. Conveyor belt 2 moves the cans along to the accumulation contoured stop bar 3. Cans are then accumulated on the conveyor belt in regular patterns up to and past the feed fingers 4 and stop fingers 5. The separate bars 6 and 7 holding the feed fingers 4 and stop fingers 5 are in the raised position at this time. However, once a sufiicient quantity of cans has passed the fingers location and has filled up the conveyor beyond the area of the feed fingers and the stop fingers then the feed fingers 4 and stop fingers 5 are lowered into their respective positions in adjacent cans (FIG. 2). The accumulation contoured stop bar 3 now lifts and cans are moved forward onto the solution tank loading platform 8. These can bodies are moved by the feed fingers 4 which now move forward. The conveyor belt 2 also provides a moving support for the can bodies. After the feed fingers have moved under the accumulation contoured stop bar and the entire batch of cans is on solution tank platform 8, against the solution tank stop bar 9, the feed fingers are lifted to an upper position 10 and return to their original raised position. The accumulation contoured stop bar 3 returns to its lower position and the stop fingers 5 are raised to allow accumulation of cans against the accumulation contoured stop bar 3. As can bodies are conducted along the processing line, this cycle is repeated time after time.

Considering now the operation of the coating bath, a batch of cans sits on the solution tank platfonn 8, and the platform is in its raised position. The can-centering plate 11 located above the tank platform has can-centering pins 13 located upon it in a regular pattern. This pattern is shown in FIG. 2. The can-centering plate 11 which has been in its upper position is now lowered together with the can pressure plate 14 to a down position and respaces the cans laterally so that they do not quite touch each other. In this way, when the can bodies 1 are lowered into the electroplating solution 15, the electroplating solution deposits evenly on the inside and outside of the can bodies without any bare spots caused by contact between adjacent can bodies. Top plate 12 (FIGS. 1, 4 and 5) is mounted above the centering plate 11 and, as described later in this disclosure, controls operation of the can immersion. The solution tank platform 8 is made of nonmetallic material and has perforations 16 at the intervals shown in FIG. 1. As the centering takes place, the stop bar 9 and side guides 17 (FIG. 2) move back to allow extra space for intercan body distance.

After the cans have been centered and respaced, the upper centering plate remains stationary, being held in place by a stop 18. The tank platform or plate 8 and the can pressure plate 14 are now lowered into the tank with the cans I mounted in between the plates. The can pressure plate has holes 16 in it to match the can centering pins 13. Holes 16 perform a dual function. One is to allow the centering pins 13 to protrude through them. The other function is to allow solution which passes through the tank platform to rise through the perforated tank platform into the cans and out through the can pressure plate. The holes 19 in the tank platform 8 have the dual function of allowing electrodes and solution to pass through. The cans and plates now descend onto the electrodes located in the bottom of the tank. A stationary electrode plate 20 is mounted in the tank and made of a nonconductive material, such as micarta or formica. Mounted at each station on the plate is a single cathode 21 with anodes 22 located around the cathode 21. There are as many anode and cathode stations as there are cans to be electroplated. When the can body is in its lowest position, the cathode 21 lies along the longitudinal axis of the can body and the anodes 22 touch the can with a press fit. Voltage is applied across the cathodes and anodes, and the plating or electrical deposition action takes place as soon as the cans establish electrical contact with the anodes. The can in contact with each anode scrapes a portion of plating material off the anode to make electrical contact with the anode. This mechanism serves as an automatic on/off switch so that current is discharged between the cathode 21 and anode 22 only when a can body is in position to be coated and at all other times, the anode 22 is promptly recoated by electrical deposition and immediately thereafter, deposition and current flow ceases. The electric potential may be reversed from that indicated above depending on the characteristics of the coating solution. Tank platform 8 is urged into its upper position by springs or counterweights 23. A line 24 runs over one or more pulleys 25, 26 and is fastened to platform 8. The platform is limited in its upward movement by stops 27. It is pushed downward by the can pressure plate 14. The can bodies are between these plates and the force imparted by the can pressure plate to the top of the can bodies is transmitted by the can bodies to the tank platform.

After the electrodeposition cycle is completed, the tank platform 8 and the pressure plate 14 move the cans upward and out of the solution and into the original upper position. The pressure plate continues its withdrawal to its high position carrying the centering plate 11 with it, and the discharge bar 28 sweeps the cans onto a second conveyor 29 made of a mesh or some other porous material. An airblast 30 from above is directed against the wet coated can bodies to remove the excess cleaning solution. The excess cleaning solution falls into a trough 31 below the conveyor and is collected for further use. As the can moves along to the next operation, a spray of deionized water is passed over the can bodies from a rinse water source 32. The can bodies are rinsed with deionized water so that when they are dried, spots will not remain on the can bodies. The can bodies are dried by an airblast 33 and then are passed further along the conveyor to the next operation which may be baking in an oven 34 or some other operation in the manufacturing process.

The coating composition used in my apparatus may be a water-dispersed coating composition, such as a partially neutralized acrylic interpolymer and an amine-aldehyde condensation product or a polyepoxide or both. Examples of such interpolymers are found listed in the patent to Donald P. Hart, US. Pat. No. 3,403,088, and assigned to P.P.G. Industries, Inc.

It is noted that these protective coatings have high dielectric strength, coat metallic articles completely, have efficient electrodepositing qualities, and result in cured films which are clear, glossy and have attractive appearance and good durability.

A cross section through the solution tank 35 is shown in FIG. 3. The discharge bar 28 is shown in its lowered position 5 where it pushes cans ofi of the perforated tank platform 8 onto the conveyor belt. The stationary electrode plate is shown with one of the numerous electrode stations in some detail. Attached to the bottom of the electrode stations at each station are conductive wires 36, 37, which are themselves coated with a plastic or other coat 39 to avoid electrical loss because of short circuiting the electric current through the solution with consequent loss of electric current and usable solution.

Threaded bolts 40 thread into nut 55 in the top plate 12 and are immovably fastened into pressure plate 14 (FIGS. 4 and 5). Rotation of these threaded bolts or screws causes the can body pressure plate 14 to move upward or downward because of threaded elements fastened to the top plate. The electrical reversing motor 45 causes the chain to turn the sprockets and 20 rotate the screws.

The motor 45 is controlled by the same master circuit that controls the motors of the various bars and plates as shown in FIG. 6. In any case, this motor drives a chain 46 around the first sprocket wheel 47, around an idler 48, the second sprocket wheel 49, third sprocket wheel 50, second idler 51, fourth sprocket wheel 52, and back around the motor drive gear 53. The idler pulleys 48, 51 may be moved in and out individually to adjust the tension on the chain 46. Four posts 54 or guide rods are fastened to the plate 12 and to the tank to support the top plate and provide guides for the movable plates. The electrical reversing motor is used to turn the sprockets 47, 49, and 52, and the attached threaded nuts Fourth, the pattern forming head stock or contoured accumulation stop bar is raised and the feed finger bar sweeps the can bodies off onto the solution tank platform and across to the solution tank stop bar.

Fifth, the feed bar raises and returns to its can body accumulating position in its raised position.

Sixth, the can pressure plate and can-centering plate lower to a point short of touching or clamping the cans.

Seventh, the can-centering plate continues to lower with centering pins entering inside the can bodies to provide can body spacing. Simultaneously, stop bars swing away and side guides are opened up sufficiently to allow a new pattern space so that liquid can swirl up between the cans.

Eighth, the can body pressure plate moves down and drives the can bodies on the tank platform into the lowered deposition position in the tank, the can flanges shear into the anodes located on the nonconductive electrode plate.

Ninth, the coating solution and electric current operate to coat the cans.

Tenth, after the cans are coated, the can pressure plate is raised and the solution tank platform follows it up until the solution tank platform is in its high position.

Eleventh, the tank platform being at its discharge position, the discharge sweep bar now lowers and sweeps the coated cans onto the second or discharge conveyor and the sweep bar now returns to its holding position. The total time cycle is about 38 seconds. It is, of course, realized that this cycle may be varied somewhat, depending upon the size, composition of cans, and the nature of the solution.

A tabular statement of operation is included for clarity. The times involved are relative and may be changed for different sizes and types of cans.

2 sec. 8 sec 1 sec. 3 sec. 4 sec. 8 sec. 4 sec. 8 sec. Stop finger barn"... Lower Coating deposits. Feed pinbar .do... Sweeps Raises.. Returns do... forto overward. head. Contouraccum. Raises do stop bar. Can center plate Rust on Rust on dov can. stop. Can pressure plate Lowers Lowers do llnisr's fur ther. Can tank platform Forced do Follows down can pres. plate up. 'Iank contour stop Swings (in Swings bar. up. down Guides Open...v .dn.. v Close. Dischargesweep bar-.. .do Lowers. Sweeps Returns (ans to up. to corrclockwise and counterclockwise to move the pressure plate up or down. The position of the motor 45, guide shafts 40, idler 48, and drive sprocket 49 and nut are shown best in FIG. 5.

A schematic control box 56 with appropriate motors is 60 other type of conveyor. The conveyor belt is continually mov- 70 Second, the cans come to rest against the accumulation contoured stop bar and back up I11 a pattern Third, after the pattern rs filled, stop fingers and feed pins are lowered into the cans.

vuyor.

The circuit of FIG. 6 can be made of any number of components and arranged in any suitable form.

The advantages of my arrangement are that a large number of can bodies may be coated in each unit of time, the can bodies are evenly and completely coated, vertical entry of the can bodies prevents air bubbles from forming on the bodies, a minimum of can body is blocked from the coating solution, littie material is used. no elements of the electrodes are movable, the system has an automatic electric on/off feature, and the can bodies are delivered clean and dry to the next operation.

The foregoing is a description of the illustrative embodiment of the invention, and it is applicant's intention in the appended claims to cover all forms which fall within the scope of the invention.

What is claimed is:

1. An apparatus for electrodepositing a coating onto can bodies comprising.

a conveyor for conducting can bodres upon its surface;

first means located at the downstream end of said conveyor for periodically halting said can bodies and causing them to collect against said first means and to pack into a regular pattern against said first means;

platform means suspended above a tank for holding a solution for supporting said can bodies after said can bodies have been moved from said conveyor to said platform means:

means for pressing said platform means and can bodies into said tank for holding a solution;

means for applying an electric potential between said can bodies and at least one electrode within said tank whereby said can bodies are coated; and

means for removing said coated can bodies from said tanks.

2. An apparatus for electrodepositing a coating onto can bodies as set forth in claim 1 in which:

said first means comprises:

a bar having contours on its upstream side which cause said can bodies on said conveyor to pack in a way that each can body touches six other can bodies to bring about the maximum number of cans per unit of area.

3. An apparatus for electrodepositing a coating onto can bodies as set forth in claim 1 in which:

said platform means comprises:

a perforated plate yieldably suspended above said tank;

vertical guide means slidably connected to said plate at several points for allowing said plate to descend into the tank with its lateral surface parallel to the horizontal; and

biasing means for urging said perforated plate upwardly.

4. An apparatus for electrodepositing a coating onto can bodies as set forth in claim 1 in which said means for pressing said platfonn and can bodies into said tank comprises:

a pressure plate mounted directly above the perforated plate; and

motor means for moving said pressure plate in a vertical direction whereby said pressure plate pushes said perforated plate into said tank and said pressure plate and said perforated plate are within said tank as said pressure plate approaches its lowered position.

5. An apparatus for electrodepositing a coating onto can bodies as set forth in claim 4 in which:

a can-centering plate is mounted for vertical reciprocating motion above said pressure plate and resting on said pressure plate;

can-centering pins are mounted on said can-centering plate in a pattern to fit inside of said cans and space each said can body a small distance from each other can body;

passageways in said pressure plate whereby said can centering pins pass through said pressure plate and enter the interior of said can bodies; and

stop means for limiting the distance that said can-centering plate follows said pressure plate in its descent whereby said centering pins remain above said tank.

6. An apparatus for electrodepositing a coating onto can bodies as set forth in claim 5 in which said electric potential applying means comprises:

a stationary electrode plate mounted in said tank;

at least one contacting electrode mounted on said plate and placed in electrical contact with said can body; and

at least one electrode mounted on said plate and spaced from said can whereby electric current may flow between said electrodes and deposit coating material onto said can body.

7. An apparatus for electroplating a coating onto can bodies as set forth in claim 6 in which:

said electrical contacting electrodes are mounted so that said can bodies, when they are being lowered into said tank, rub against said electrical contacting electrodes and scrape the coating off said electrodes whereby an electrical contact is made between said electrodes and said can bodies.

8. An apparatus for electrodepositing a coating onto can bodies as set forth in claim 6 together comprising:

a first bar mounted over said conveyor with its long axis transverse to the direction of travel of said conveyor and parallel to the main surface of said conveyor;

motor means for raising and lowering said first bar when said can bodies have filled said conveyor to a predetermined amount; and

finger means mounted on the bottom side of said first bar for insertion into a first row of said can bodies to halt travel of said can bodies on said conveyor.

9. An apparatus for electrodepositing a coating onto can bodies as set forth in claim 8 further comprising:

a second bar mounted over said conveyor with its long axis parallel to and adjacent to said first bar and being located between said periodic halting means and said first bar, and above a second row of cans;

motor means for moving said second bar from a raised position adjacent said first bar to a lowered position adjacent the tops of said can bodies, then laterally past the edge of said platform means and thence upwardly and return to the first raised position; and

finger means mounted on the bottom side of said second bar for insertion into said second row of can bodies whereby when said bar having contours on its upstream side is raised, said stop finger means moves said can bodies onto said means platform and against a solution tank stop bar.

10. An apparatus for electroplating a coating onto can bodies as set forth in claim 9 further comprising:

a discharge bar mounted between said conveyor and said tank for moving said coated can bodies from said platform means onto a further conveyor.

i i I & I 

2. An apparatus for electrodepositing a coating onto can bodies as set forth in claim 1 in which: said first means comprises: a bar having contours on its upstream side which cause said can bodies on said conveyor to pack in a way that each can body touches six other can bodies to bring about the maximum number of cans per unit of area.
 3. An apparatus for electrodepositing a coating onto can bodies as set forth in claim 1 in which: said platform means comprises: a perforated plate yieldably suspended above said tank; vertical guide means slidably connected to said plate at several points for allowing said plate to descend into the tank with its lateral surface parallel to the horizontal; and biasing means for urging said perforated plate upwardly.
 4. An apparatus for electrodepositing a coating onto can bodies as set forth in claim 1 in which said means for pressing said platform and can bodies into said tank comprises: a pressure plate mounted directly above the perforated plate; and motor means for moving said pressure plate in a vertical direction whereby said pressure plate pushes said perforated plate into said tank and said pressure plate and said perforated plate are within said tank as said pressure plate approaches its lowered position.
 5. An apparatus for electrodepositing a coating onto can bodies as set forth in claim 4 in which: a can-centering plate is mounted for vertical reciprocating motion above said pressure plate and resting on said pressure plate; can-centering pins are mounted on said can-centering plate in a pattern to fit inside of said cans and space each said can body a small distance from each other can body; passageways in said pressure plate whereby said can centering pins pass through said pressure plate and enter the interior of said can bodies; and stop means for limiting the distance that said can-centering plate follows said pressure plate in its descent whereby said centering pins remain above said tank.
 6. An apparatus for electrodepositing a coating onto can bodies as set forth in claim 5 in which said electric potential applying means comprises: a stationary electrode plate mounted in said tank; at least one contacting electrode mounted on said plate and placed in electrical contact with said can body; and at least one electrode mounted on said plate and spaced from said can whereby electric current may flow between said electrodes and deposit coating material onto said can body.
 7. An apparatus for electroplating a coating onto can bodies as set forth in claim 6 in which: said electrical contacting electrodes are mounted so that said can bodies, when they are being lowered into said tank, rub against said electrical contacting electrodes and scrape the coating off said electrodes whereby an electrical contact is made between said electrodes and said can bodies.
 8. An apparatus for electrodepositing a coating onto can bodies as set forth in claim 6 together comprising: a first bar mounted over said conveyor with its long axis transverse to the direction of travel of said conveyor and parallel to the main surface of said conveyor; motor means for raising and lowering said first bar when said can bodies have filled said conveyor to a predetermined amount; and finger means mounted on the bottom side of said first bar for insertion into a first row of said can bodies to halt travel of said can bodies on said conveyor.
 9. An apparatus for electrodepositing a coating onto can bodies as set forth in claim 8 further comprising: a second bar mounted over said conveyor with its long axis parallel to and adjacent to said first bar and bEing located between said periodic halting means and said first bar, and above a second row of cans; motor means for moving said second bar from a raised position adjacent said first bar to a lowered position adjacent the tops of said can bodies, then laterally past the edge of said platform means and thence upwardly and return to the first raised position; and finger means mounted on the bottom side of said second bar for insertion into said second row of can bodies whereby when said bar having contours on its upstream side is raised, said stop finger means moves said can bodies onto said means platform and against a solution tank stop bar.
 10. An apparatus for electroplating a coating onto can bodies as set forth in claim 9 further comprising: a discharge bar mounted between said conveyor and said tank for moving said coated can bodies from said platform means onto a further conveyor. 